A variety of advanced imaging devices have been developed over the years for ophthalmic imaging, diagnostics and surgery. For some applications, these imaging devices perform best when their optical axis is aligned with an optical axis of the imaged eye. Once the optical axis of the eye is aligned with the optical axis of the imaging device, some imaging devices enhance the precision of the imaging process by immobilizing the eye in the aligned position with the help of a patient interface or eye-docking system. As the precision of the imaging devices improves, the demand for eye-docking systems which provide more precise alignment also increases.
In typical existing systems the alignment is guided manually. The operator can direct the patient verbally, manually orient the eyeball, or adjust portions of the imaging device, such as its objective or gantry, or any combination of the above. These adjustments are performed iteratively during the docking process. However, the inaccuracy of these manual approaches can make the docking process quite time consuming and frustrating, and still fall short of achieving high quality alignment. Because of the limited precision of the manually guided alignment, the patient interface often ends up docked to the eye in an off-center position, the eye's optical axis tilted and the eye laterally misplaced relative to that of the imaging system.
Some imaging systems use guidance mechanisms that promise improvements for the alignment process. In some systems, such as in some surgical systems using excimer lasers, the alignment is aided by a fixation light. The fixation light can be centered with the optical axis of the imaging system. The patient can be instructed to train his eye on the fixation light. This fixation can align the patient's eye with the imaging system. However, even these fixation light systems have limitations.